Study and visualization of the concentration dependence on the refractive index of liquids

Abstract

Laser based measurement have been found in early 1900 indirectly by Albert Einstein during the research of photoelectric effects and until now, its application still growing. The main objective in this project is to study the dependence of refractive index (RI) on the concentration by laser based measurement. Low power laser pointer with the output of 1 mW and the wavelength of 630 to 670 nm are employed as a light source. The phenomenon of refraction occurs when a monochromatic laser light source passed through the prism which full with liquids. In this study two types of liquids consist of sugar and salt solution were utilized as samples. Generally, refraction happened when the source light travel through two different medium like air and sugar water because of the slightly change of speed of light. Hence, the output of light from the second medium were refracted far away from the normal line and it is called the index of refraction, n where can be determined by using Snell's Law. The concentration of these liquids were carried is from 5% to 65%. The RI value for both sample are proportional with its concentrations. The experimental value than has been compared with literature value. Then, based on the experimental set up, an interactive 'Easy_GUI' language was developed to determine the RI value for the future accessibility.